L.P. Aref’eva – Ph.D (Phys.-Math.), Associate Professor, Don State Technical University (Rostov-on-Don)

E-mail: Ludmilochka529@mail.ru

Yu.V. Dolgachev – Ph.D. (Eng.), Associate Professor, Don State Technical University (Rostov-on-Don)

E-mail: yudol@mail.ru

Statement of the problem. The main directions of the modern materials science are the creation of new and improving the quality of existing materials. Rough surfaces have the property of self-similarity, therefore, fractal analysis methods can be applied to them. Using the value of the fractal dimension, we can uniquely describe the complexity of the surface morphology. Scanning probe microscopy allows you to visualize the surface of the material and determine its characteristics, in particular, roughness, waviness, fractal dimension. 

Aim of the work. The aim of our work was obtained and analyzed the topology of the polished surface of structural carbon and tool alloy steels, as well as establishing the fractal dimension of surfaces. 

Results. In this work, we studied the surface of 1040 (ASTM) and T31507 steels by scanning tunneling microscopy. The optical emission analysis was performed to clarify the chemical composition of the samples. Next, the samples were ground and polished. Surface etching was not carried out. The surface topology of the samples was obtained using a scanning tunneling microscope "UMKA-02-E" in direct current mode. The resulting two-dimensional and three-dimensional images were processed and analyzed in the Gwyddion modular data analysis program. Analysis of the surface of the samples allows us to conclude that the structural formations are uniformly distributed and have dimensions of the order of tens of nanometers. Analysis of surface profiles shows that the structural formations have one peak and their shape and sizes are similar. Thus, fractal analysis can be applied to the surfaces under investigation. The fractal dimension of surfaces was determined by the method of counting cubes. It was found that for a sample of T31507 steel Df = 2.448 ± 0.013, for steel 1040 (ASTM) Df = 2.43553 ± 0.015. The average roughness is 72,27 and 45,21 nm for the surfaces of steels T31507 and 1040 (ASTM), respectively. Also we determine the value of relief waviness. Our results are consistent with the theoretical concepts about correlation values of the roughness and the fractal dimension of surface. 

Practical significance. The analysis of the surface topology showed that scanning tunneling microscopy makes it possible to uniquely characterize the micro- and nanostructure of steel.

1. Adamchuk V.K., Balizh K.S., Bykov V.A., Dobrotvorskij A.M., Mal'cev A.A., Pushko S.V., Sen'kovskij B.V., Ul'yanov P.G., Usachev D.YU., Cygankov A.B. Sposob metallograficheskogo analiza. Byulleten'. №20. 2014. 
2. Douketis C., Wang Z., Haslett T. L., Moskovits M. Fractal character of cold-deposited silver films determined by low-temperature scanning tunneling microscopy. Physical Review B. 1995. V. 51. № 16. P. 51.
3. Zahn W., Zosch A. The dependance of fractal dimension on measuring conditions of scanning probe microscopy. Fresenius J. Analen Chem. 1999.  V. 365. P. 168–172.
4. Beech I.B. The potential use of atomic force microscopy for studying corrosion of metals in the presence of bacterial biofilms – an overview. International Biodeterioration and Biodegradation. 1996. P. 141–149.
5. Man J., Valtr M., Weidner A., Petrenec M., Obrtlík K., Polák J. AFM study of surface relief evolution in 316L steel fatigued at low and high temperatures. Procedia Engineering. 2010. V. 2. P. 1625–1633.
6. Sdobnyakov N.YU. Zykov T.YU., Bazulev A.N., Antonov A.S. Opredelenie fraktal'noj razmernosti ostrovkovyh plenok zolota na slyude. Vestnik Tverskogo gosudarstvennogo un-ta. Ser. Fizika. 2009. Vyp. 6. S. 112–119.
7. Zykov T.YU., Sdobnyakov N.YU., Samsonov V.M., Bazulev A.N., Antonov A.S. Issledovanie morfologii rel'efa poverhnosti zolota na slyude metodom skaniruyushchej tunnel'noj mikroskopii. Kondensirovannye sredy i mezhfaznye granicy. 2009. T. 11. № 4. S. 309–313.
8. SHlyahova G.V., Barannikova S.A., Zuev L.B., Bochkareva A.V. Primenenie metodov ASM dlya izucheniya stali 40H13 v razlich-nyh strukturnyh sostoyaniyah. Sb. tezisov XV Mezhdunar. shkoly-seminara «Evolyuciya defektnyh struktur v kondensiro-vannyh sredah». 2018. S. 104.
9. SHlyahova G.V., Zuev L.B., Popova E.A. Ocenka parametrov struktury konstrukcionnoj uglerodistoj stali metodami ASM. Vestnik Tambovskogo universiteta. Ser. Estestvennye i tekhnicheskie nauki. Prilozhenie k zhurnalu. 2018. T. 23. 
10. № 123. S. 581–584.
11. SHlyahova G.V., Zuev L.B., Popova E.A. Issledovanie uglerodistoj stali metolom atomno-silovoj mikroskopii. Sb. trudov mezhdunar. konf. «Mekhanika, resurs i diagnostika materialov i konstrukcij XII» 2018. S. 302.
12. Karban' O.V., Lad'yanov V.I., Maklecov V.G., Reshetnikov S.M., Borisova E.M. Primenenie skaniruyushchej zondovoj mikro-skopii pri korrozionnyh issledovaniyah stali 12H18N10T v razlichnyh sredah. Vestnik Udmurtskogo un-ta. 2014. Vyp. 2. S. 5–12.
13. Hogstrom R., Korpelainen V., Riski K., Heinonen M. Atomic force microscopy studies of surface contamination on stainless steel weights. Metrologia. 2010. V. 47. P. 670–676.
14. Kovács D., Dobránszky J., Bonyár A. Effect of different active screen hole sizes on the surface characteristic of plasma nitrided steel. Results in Physics. 2019. V. 12. P.1311–1318.
15. Li Y., He Y., Xiu JJ., Wang W., Zhu YJ, Hu B. Wear and corrosion properties of AISI 420 martensitic stainless steel treated by active screen plasma nitriding. Surf. Coat. Technol. 2017. V. 329. P. 184–192.
16. Korh M.K., Korh YU.V., Rigmant M.B., Kazanceva N.V., Vinogradova N.I. Ispol'zovanie metoda zonda Kel'vina dlya kon-trolya fazovogo sostava austenitnoferritnoj hromonikelevoj stali. Defektoskopiya. 2016. №11. S. 59–69. 
17. Blesman A.I., Kas'yanenko V.A. Skaniruyushchaya zondovaya mikroskopiya poverhnosti stali 38H2MYUA posle ionnoj implanta-cii gadoliniya, ittriya, skandiya i titana. V sb. «Aktual'nye problemy sovremennoj nauki» Materialy VIII Regional'noj nauch.-prakt. konf. s mezhdunar. uchastiem. 2019. S. 7–10.
18. Brylkin YU.V., Kusov A.L. Sootnoshenie fraktal'noj razmernosti i razlichnoj sherohovatosti dlya obrazcov medi. Fiziko-himicheskie aspekty izucheniya klasterov, nanostruktur i nanomaterialov: mezhvuz. sb. nauch. tr.. Pod obshch. red. V.M. Samso-nova, N.YU. Sdobnyakova. Vyp. 5. Tver': Tverskoj gosudarstvennyj un-t. 2013. S. 33–38.
19. Wang Q., Huang C., Zhang L. Microstructure and tribological properties of plasma nitriding cast CoCrMo alloy. J. Mater. Sci. Technol. 2012. V. 28. P. 60–65.
20. Isanova V.S., Balankin A.S., Bunin I.ZH., Oksogoev A.A. Sinergetika i fraktaly v materialovedenii. M.: Nauka. 1994. 383 s.
21. Aref'eva L.P., SHebzuhova I.G. Smachivanie i anizotropiya mezhfaznoj energii na granice kontakta nanokristallov indiya s orientirovannoj podlozhkoj. Fiziko-himicheskie aspekty izucheniya klasterov, nanostruktur i nanomaterialov: Mezhvuz. sb. nauch. tr.. Pod obshch. redakciej V.M. Samsonova, N.Yu. Sdobnyakova. Vyp. 10. Tver': Tverskoj gosudarstvennyj un-t. 2018. S. 27–34.
22. Aref'eva L.P., SHebzuhova I.G., Sahno T.A., SHahova L.S. Primenenie atomno-silovoj mikroskopii dlya issledovaniya ani-zotropii mezhfaznoj energii na granice metall-orientirovannaya podlozhka. Fiziko-himicheskie aspekty izucheniya klaste-rov, nanostruktur i nanomaterialov: Mezhvuz. sb. nauch. tr.. Pod obshchej redakciej V.M. Samsonova, N.YU. Sdobnyakova. Vyp. 11. Tver': Tverskoj gosudarstvennyj un-t. 2019. S. 16–25.
23. Aref’eva L.P. Blinov A.V., Kravtsov A.A., Shebzukhova I.G., Serov A.V. Features Wetting and Anisotropy of Interfacial Energy in a Metal Particle-Silicon System. Matec. Web. of Conferences. 2018. V. 226. Art. № 03009. 7 p.
24. Duka V.V., Fedosov V.V., Dolgachev YU.V., Mekhanicheskie svojstva kompozicionnogo materiala na baze doevtektoidnoj stali. Sb. statej Mezhdunar. nauch.-prakt. konf. «Issledovanie, razrabotka i primenenie vysokih tekhnologij v promyshlennosti». 2018. S. 84.
25. Pustovojt V.N., Duka V.V., Dolgachev YU.V. Scenarij rosta treshchiny v stali so strukturoj ferritno-martensitnogo kompo-zita. Izv. Volgogradskogo gosudarstvennogo tekhnicheskogo un-ta. 2017. № 10 (205). S. 156–160.
26. Duka V.V., Pustovoit V.N., Ostapenko D.A., Aref`eva L.P., Dombrovskij Yu.M. The use of the atomic force microscopy to investigate the structure of steel 14G2. IOP Conf. Series Materials Science and Engineering. 2019. V. 680. Art. № 012023. 7 p.
27. Nečas D, Klapetek P. Gwyddion: an open-source software for SPM data analysis. J. Phys. 2012. V. 10. P. 181–185.